Scientists Concerned Over Guadalupe Fur Seal Deaths

The Guadalupe fur seal is currently classified as a threatened species, and a new report from the National Oceanic and Atmospheric Administration has raised some new concerns about the seals, which are mostly located off the coast of Southern California and Mexico.

The NOAA announcement signifies an “unusual mortality event” for the fur seals, and such events are described as “a stranding that is unexpected; (one that) involves a significant die-off of any marine mammal population; and demands immediate response.” Some eighty seals were discovered stranded along central California shores since the beginning of the year; that’s about eight times more seals than what is considered normal for the species.

According to NOAA, close to half of the seals (38) were found alive, while the remaining 42 were found dead. Typically, only about 10 to 12 Guadalupe fur seals are stranded per calendar year. Most of the stranded seals, said Marine Mammal Center scientist Tenaya Norris, were born in 2014. The Sausalito, California-based Marine Mammal Center, together with Sea World, is one of only two institutions that have the official responsibility to rehabilitate stranded Guadalupe fur seals.

Regardless whether the stranded seals were found dead or alive, all of them were in very poor shape, looking emaciated upon their discovery. This may be because of unusually warm conditions in the eastern Pacific, which has been the trend for about two years to date. NOAA Southwest Fisheries Science Center director of environmental research Toby Garfield stated that these unusual conditions may have been caused by a warm water “blob” and a related high-pressure ridge in the gulf of Alaska; these two have combined to change weather trends in the area, resulting in atypically warm weather in the West Coast region.

Due to the warm water conditions, Garfield added, several forage fish species that the Guadalupe fur seals traditionally chase after have changed their travel patterns. Some of these fish species have specifically swam to the north to get away from the warm water conditions, while others located south of the fur seals’ range have moved into the region, or are beginning to move there. This may be the main reason why the seals are becoming emaciated – with their usual food sources gone, they have changed their diet and are struggling to adjust. NOAA officials also believe that the warm water conditions may also be connected to 2015’s other “unusual mortality event,” this time involving fin whales, humpbacks, and other large whale species.

While not technically endangered, the Guadalupe fur seal has been classified as a threatened species under the Endangered Species Act since 1967, or almost 50 years ago. It is also being protected by the Marine Mammal Protection Act. The species, NOAA explained, was nearly killed off in the late 19th century, and while it was nearly hunted to extinction in those days, it has since recovered, with the species now numbering about 15,000 seals. Guadalupe fur seals breed in a very exclusive range, almost exclusively covering Guadalupe Island, which is located off the coast of Baja California, Mexico.

For the meantime, scientists will continue to monitor the seals closely, but no additional protection will be launched in the meantime. “We have a working group, experts from all around the country, that are weighing (their options),” said NOAA stranding coordinator Justin Viezbicke.